Power-driven jackhammer



y 1952 o. s. COATES 2,597,292

POWER- DRIVEN JACKHAMMER Filed April 30, 1949 2 SHEETS-SHEET l Snventor (Ittorneg May 20, 1952 o. s. COATES POWER-DRIVEN JACKHAMMER 2 SHEETSSHEET 2 3nventor Filed April 30, 1949 Patented May 20, 1952 POWER-DRIVEN JAOKHAMMER Oscar S. Coates, Rock Springs, Ariz.

' Application April 30, 1949, Serial N 0. 90,927

I 4 Claims. (Cl. 255--42) 1 This invention pertainsto power driven jack hammers. I

One of the objects of this invention is toprovide a jack hammer having mechanism foroonl verting rotary motion from a driving shaft to an series of mechanically produced blows adapted to drive drills, drill points or the like;

Another object is to provide a jack hammer having a cylindrical case with an airpiston working with reciprocating hammer in saidcase to furnish air pressure for use in cleaningout drill holes;

Another object isto" provide a-jack:-hammer "having a-reciprocating striking'head with means for coordinately rotating the striking and drill:

holding means'a predetermineddegree each time a blow is struck;

1 Another object is to provide a jack hammer as above described with means for supplying water to a hole being drilled.

. Atfurther object is to provide ailight portable jack hammer Which-can be 'efliciently. driven by .2 a flexible shaftv turned by alight motor ofsmall :horsepower;

A still further object is to provide a jack ham 1 mer, as above; mentioned, with conveniently; po-

6 sitioned'handles and operating lever forcontrolling the application of power to the driving mechgamsm.

' Other objects will appear hereinafter.

- :IV attain the foregoing objects bymeans ofthe mechanism; and combination of;parts shown in the accompanying drawings in which .Figure 4 is a vertical elevation of the jack ham mer, as viewed from theright side of thedevice asshown in Figure 1;

- Figured is a vertical sectional elevation of the column bar. lifting mechanism, taken substan; tially on lines 5V5, Fig. 2; drawn on an enlarged scale;

Figure 6 is a section of the jack hammer case taken on lines 6-6 of Fig. 1; and

Figure 7 is a side elevation of the upper portion of the jack hammer column bar withthepiston holding collar thereon shown in section.

- 1 Similarnumeralsrefer to similar parts in the several views. 5 .-The-mechanism of the jack hammer? is enclosed 30 v groove whichreceives clutch'iork 84 pivoted at 85 within a forged orcast cylindrical case 2 to the top of whichhandles 3are attached 'Ifheupper end of the case isclosed by plate 4 and the interioriportionrofgthe case justbelow this constitutes an air cylinder 6. f The bottom of the case is closed by aforgedportion l to the bottom of which the hammer housing 9 is secured by rods 5. Drill chuckhousing l9 is secured to h ammer housing by;bolts; l2. Theclosure 'I has an axial bore l I.

A ifiattened face; I2 is formedon the right side of case 2 and provided with a, beveled hole It 1 which receives beveled boss [6, on the-inner portion of clutch housing] 8.

Withinthe clutch housing is a drive shaft which extends, radially relative to the axis of case 'Zand V "carries bevel drivinggear 2| on its inner end and a splined shaft receiving portion on its outer'end. i The inner portion of, shaft isjournalled in the inner portion of housingl8 and the outer portion 22 in theouter wall24 A sleeve 89- surrounds and islkeyed to the inner portion. of the-drive shaft, while the inner end of outer portion22 turns freely in-the; outer portion of this: sleeve.

A clutchcone 8| is keyed to the outer portion. 22

- of the drive .-shaft, and a vmating clutchshellj 82 is slidably. keyed on sleeve 80 so that it will move a from engaged, positionon cone 8] to adiseng'a-ged position separated thereiromr Clutch. shell 82 is provided with a hub 83 .having ana'nnular .-and supporting a lever plate 86. Trigger 8lb'e'ars on thisdplate and is adapted to move itirom V. the engaged position shown, to a disengagedposition against theurge ofclutch spring 89.

A threaded boss 23 on wa11A24 surrounds the o outer, portion of shaft 20 to; provide means. for ,attachingla flexible shaitcoupling (not shown).

Axially within case. 2 isarecipro'cating and ro- .;ta,ting column bar 30. The lowerlportion oi this bar is formed as a hammer 3'21 'Thelower'enlargedv cylindrical:journaliportion '33fbears in hammer housing 9 in which it slides and rotates.

(Above thehammerthe columnfbarshaft is reduced in size and bear s inthe inneirjbore ofv cam roller lifting sleeve. w

Above sleeve SA-thecolumn bartshaft is re- ,duced in size to providea shoulder anagis threaded .to receive stop c zollar 37 @Beyond' thisthreaded portion the shaft isagain reduced infsiae; and

machined to provide a: plurality of spiral splines 39. The upper end.;is then reducedin size to form a journal to bear in bushing 49; This} bushing isof ree to turn on the upper end of thecolumn bar and is retained by screw .4 l rwhic'hhas a dog point engaging in an annular groove formed in the journal portion of the column bar near its upper end. l-tlng or plate 42 is forced onto busnlng 4u and has two upwardly extending and diverglng bars 43 which form a stirrup shaped structure to support piston 44 and attach it to the column bar. The upper ends of bars 43 are welded to the lower face of piston 44 at opposite points near its edge and the space between them is made adequate to admit the air and water pipe 99 which extends diametrically through cylinder 5. Piston 44 operates up and down within the upper part of cylinder 6 and above pipe 90, but does not rotate with the column bar.

Within the annular space 45 above cylindrical hammer portion 33 is the hammer or striking spring 45. The lower end of this spring bears on the upper annular face of hammer portion 33 and the upper end bears on the lower face or case closure I.

Lifting sleeve 34 is provided with key way grooves 35 and is fitted into gear bearing sleeve 4| to have a free sliding lit. Bearing sleeve 4! is, in turn, tightly pressed into bore ii in the bottom closure I of case 2. Keys 49 are fitted into the annulus of closure 1 surrounding bore II, and extend through slots in sleeve 4|, into grooves 35 in lifting sleeve 34. Lifting sleeve 34 1s rree to slice up and down in bearing sleeve 4 I, but is restrained from rotation by keys 49. The midportlon of column bar 36 Journals in lifting sleeve 34 and is free to turn therein.

Bosses 5| extend radially from each side of lilting sleeve 34 and journal cam rollers 52. These rollers are positioned to roll on the upwardly disposed faces of arcuate cams 54 which are formed on the upper face of driven bevel gear 53. This gear is journalled on bearing sleeve 4| and is retained by a 0 ring 55 locked in groove 55 at the top of this sleeve. It meshes with driving gear 2|.

In the upper portion of case 2 a ratchet wheel 50 is supported between plates 6| which restrains its upward and downward movement.

The hub 68 of ratchet wheel 69 is provided with a hole 66 to receive the splined portion 64 of column bar 30. This hole is provided with grooves and lands shaped to mate the spiral splines 39 and the grooves between them. Pawls 61 attached to the case engage teeth 63 on wheel 69 and detain it from counterclockwise rotation as viewed from above (Figure 3). On the up stroke column bar 30 tends to rotate counterclockwise through the hub of wheel 60, and wheel 60 tends to rotate clockwise. Column bar 30 has more resistance to rotation, due to its frictional support within parts of case 2, and its inertia, than wheel 60 and therefore wheel 60 turns clockwise and column bar 30 does not turn. On the down stroke column bar tends to turn clockwise (as viewed from above) and ratchet wheel 60 tends to turn counterclockwise. Since pawls 61 detain counterclockwise rotation of wheel 60 column bar is forced to rotate clockwise. The degree of rotation depends on the pitch of spiral splines 39, and the length of the stroke.

A cylindrical drill chuck H fits loosely within chuck housing II]. A striking bar is formed at the lower end of column bar 30 below the hammer portion 33. This striking bar extends into an axial bore in the upper portion of drill chuck H. The striking bar is provided with splines 69 which mate grooves in the drill chuck H, and impart rotary motion from the striking bar 10 to the chuck 1|. Chuck housing I0 is releasably attached to sleeve 9 by bolts :2 extending downward through lugs 14 on sleeves 9 and through similar lugs ma on chuck housing l0. Springs 13 are between the nuts at the lower ends of bolts -l2 and lugs on the chuck housing l0. Hexagon drill I6 is retained in an axlally extending mating hexagonal hole in the lower end of drill chuck H by swing latch or bail ll. Retention of drill T5 in chuck H by these devices is well known to the art.

The column bar 30 is drilled axially as shown at 18, Figures 2 and 3, to receive air and water tube 19 which connects to diametrically disposed tube at the top. Drill 16 is axially bored, and its bore hole mates with the bore hole in the bottom of column bar 30.

In use the drill 76 is inserted in the chuck in the usual manner. The outer end 22 of the drive shaft 20 is connected to a flexible shaft operated by a small gasoline engine or electric motor. If the hole is to be drilled dry no water connection is made to tube 90. Driving gear 2| is then turned by power transmitted through clutch members bl and 82. Gear 53 rotates arcuate cams 54 which raise rollers 52, sleeve 34, stop collar 31 and column bar 30 against the urge of spring 46. When the lips 92 of the cams pass beneath the rollers bl, cal av 10 forced downward by spring 45. This causes hammer 32 to strike the upper end of drill 16. The number of blows struck is governed by the speed of the drive shaft and the ratio of gears 2| and 53.

As column bar shaft 30 reciprocates spiral splines 39 traveling axially on the hub hole or ratchet wheel 60 rotate it a predetermined distance as above explained. The mechanism including ratchet wheel 60, pawls 61, and the splined portion 39 of striking bar 30, constitutes a means for rotating drill 16. This rotary mo vement is imparted to drill 16 through chuck II to keep it from binding in the hole.

coincidentally piston 44 operates in cylinder 6. Air is drawn in through intake valve 93 and forced out through outlet valve 94 to transverse pipe 90, and thence down through tube 19 which slides in the axial bore 18 of column bar 39. This air is in turn forced through the bore of drill 16. Normally the outer end of pipe 90 is closed by cap 96.

When water is required for drilling rather than air, cap 96 is removed from pipe 90, and a water hose connected. Water may then be forced through tube 19 and air forced along with it. Valve 94 keeps water out of cylinder 6, and air pumping action may be stopped by holding inlet valve 93 open. Breather hole I00 is drilled in case 2 to relieve pressure below piston 44.

Summarizing operational use of the drill: shaft 22 is driven by a motor;'operation is controlled by trigger 81 which controls the clutch; the gears and rotary cams raise the column bar shaft 30 and its attached parts against tension of spring 46; the column bar shaft turns as it reciprocates, and either air or water may be forced down the shaft and drill. In normal use the drill may be held by handles 3, and drill l6 chucked in the conventional manner.

I claim:

1. A power driven jack hammer, including, in combination, a cylindrical case body; an axially bored column bar axially operative therein; a hammer portion on the lower end of said column bar having a striking bar at its lower end; a drill chuck adapted to receive said strik ng bar at its upper end having means for retaining a drill in its lower end, a drill having an axial opening secured-in said chuck, a spring within said 'c'ase surrounding said column bar extending between ally operata-ble clutch to control rotation from said drive shaft to said gears, and means for clearing the hole drilled by said drill comprising a cylinder formed within the upper end of said cylindrical body, a-piston attached to the upper end of said column bar, operative in said cylinder, an air inlet valve opening into said cylinder, an air outlet valve and a pipe leading from said outlet valve to the axial bore of said column bar and extending therein in slidable air tight relation thereto.

,2. A power driven jack hammer comprising in combination a cylindrical case having radially extending handles at the top, an air cylinder formed within its top portion, a bottom closure having an axial bore, an axially bored sleeve secured to the lower end of said case forming a hammer housing on its lower end, and an axially bored drill chuck housing detachably secured to said sleeve; a column bar axially operable in said case and having an axial bore, a hammer portion adjacent its lower end having an enlarged journal portion bearing in said hammer housing, a striking bar below said enlarged journal portion, a portion above said enlarged journal portion adapted to receive a striking spring, and spiral splines formed on the upper portion of said column bar; a striking spring surrounding said hammer portion engaging between said enlarged bearing portion at its bottom and said case bottom closure at its top normally urging said column bar downward; mechanism for axially reciprocating said column bar including a lifting sleeve secured to said column bar journalled for axial sliding motion within the axial bore in the bottom closure of said case having sliding key slots; keys within the bore of said case closure slidably engaging in said slots in said lifting sleeve to restrain it from rotation, radially extending cam rollers attached to the upper portion of said lifting sleeve, a driven bevel gear journalled on said lifting sleeve having cams on its upper surface cooperative with said cam rollers and shaped to produce a slow lift and a quick release therefrom; a driving bevel gear meshing with said driven bevel gear keyed to a radially extending shaftjournalled in said case; mechanism including a clutch for rotating said radially extending shaft; a drill chuck operative in said drill chuck housing adapted to receive said striking bar at its upper end keyed to rotate therewith and adapted to receive a hexagon shaped axially bored drill at its lower end; mechanism for forcing air through the bore in said column bar to the drill in said chuck including a piston s cured to the upper end of. said column bar and operative in the air cylinder of said case, an inlet valve in the top of said cylinder, an outlet valve in the top of said cylinder connected to a pipe axially positioned in said case and fitted into the axial bore of said column bar in air tight relation therewith; and mechanism for rotating said column bar including a ratchet wheel journalled within said case having :a 'hub bored and provided with grooves and lands bearing on and cooperative with (the spira1-splined portion of said column bar, pawls within said case engaging said ratchet wheel to permit its rotation in one direction anddetainiits rotation in the opposite direction, 'wherebyz'sai'd column bar will be rotated by axial movement of said splined portion therethrough.

contact with said hammer portion,'-the combination therewith of mechanism for' rotating-said columnbar and a drill held in operative contact with thehammer portion thereon, coincidental to its axial striking motion, including spiral splines formed on the upper portion of said column bar, a ratchet wheel journalled within said case having a hub provided with lands and grooves adapted to operatively receive said splined portion of said column bar; pawls attached to said case adapted to engage said ratchet wheel and detain it from rotation in one direction, a striking bar formed on the lower end of said column bar hammer portion; a drill chuck operative in the drill chuck housing of said case having an axial opening adapted to receive said striking bar at its upper end in axially slidable relation thereto and to receive a drill in fixed rotational relation at its lower end, and splines operative between said striking bar and said opening in the upper end of said chuck so that rotary movement of said column bar is communicated to said chuck.

4. A power driven jack hammer comprising, in combination, a cylindrical case having radially extending handles at the top, an air cylinder formed within its top portion, a bottom closure having an axial bore, an axially bored sleeve secured to the lower end of said case forming a hammer housing on its lower end, and an axially bored drill chuck housing detachably secured to said sleeve; a column bar axially operating in said case, having an axial bore, a striking bar at its lower end, an enlarged hammer portion thereabove, a journal portion above said enlarged hammer portion, and a portion of reduced size thereabov having spiral splines and terminating in a collar journal; a striking spring surrounding the said hammer portion of said column bar, engaging between the enlargement thereof and said case bottom and normally urging said column "bar downward, a lifting sleeve bearing on said journal portion of said column bar and secured thereto to communicate lifting motion to said column bar against the urge of said spring; said lifting sleeve having longitudinal key slots; keys fitted into the axial bore in the bottom of said case and slidably engaging the key slots in said lifting sleeve to restrain it from rotation; radially extending cam rollers attached to said lifting sleeve; a driven bevel gear journalled on said lifting sleeve below said cam rollers and journalled on said case bottom closure to resist downward thrust, having cams on its upper surface cooperative with said cam rollers to produce a slow lift and quick release therefrom; a driving bevel gear meshing with said driven gear operating on a radially extending shaft journalled in said case; a drill chuck operative in said' drill chuck housing adapted to slidably receive said striking bar at its upper end, keyed to rotate therewith, and having an axially disposed hexagonal hole within its bottom portion; a hexagon drill bar having an axial bore fitted into the lower end of said drill chuck; a resiliently supported latching bail securing said drill bar in said chuck; a piston secured to the upper end of said column bar on a bearing collar, andbperating in said air cylinder; valves operating in said cylinder to draw air therein and expel it therefrom, and a tube connected to said cylinder through one of said valves adapted to carry air therefrom to the axial bore of said column bar; and a ratchet wheel journalled within said case having a hub formed with a centrally positioned opening having grooves and lands adapted to slidably receive the splined portion of said column bar; pawls on said case cooperative with said ratchet wheel to restrain its rotation in one direction whereby 8 said column bar will be rotated by axial move ment of its said splined portion through the hub of said wheel.

OSCAR S. COATES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

